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Title: ALMA IMAGING OF THE CO (6-5) LINE EMISSION IN NGC 7130

Abstract

In this paper, we report our high-resolution (0.″20 × 0.″14 or ∼70 × 49 pc) observations of the CO(6-5) line emission, which probes warm and dense molecular gas, and the 434 μm dust continuum in the nuclear region of NGC 7130, obtained with the Atacama Large Millimeter Array (ALMA). The CO line and dust continuum fluxes detected in our ALMA observations are 1230 ± 74 Jy km s{sup −1} and 814 ± 52 mJy, respectively, which account for 100% and 51% of their total fluxes. We find that the CO(6-5) and dust emissions are generally spatially correlated, but their brightest peaks show an offset of ∼70 pc, suggesting that the gas and dust emissions may start decoupling at this physical scale. The brightest peak of the CO(6-5) emission does not spatially correspond to the radio continuum peak, which is likely dominated by an active galactic nucleus (AGN). This, together with our additional quantitative analysis, suggests that the heating contribution of the AGN to the CO(6-5) emission in NGC 7130 is negligible. The CO(6-5) and the extinction-corrected Pa-α maps display striking differences, suggestive of either a breakdown of the correlation between warm dense gas and star formation at linear scales of <100 pc or a large uncertainty in ourmore » extinction correction to the observed Pa-α image. Over a larger scale of ∼2.1 kpc, the double-lobed structure found in the CO(6-5) emission agrees well with the dust lanes in the optical/near-infrared images.« less

Authors:
 [1];  [2]; ; ;  [3];  [4];  [5];  [6];  [7];  [8];  [9];  [10];  [11];  [12]
  1. Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011 (China)
  2. National Astronomical Observatories of China, Chinese Academy of Sciences, Beijing 100012 (China)
  3. Infrared Processing and Analysis Center, California Institute of Technology 100-22, Pasadena, CA 91125 (United States)
  4. Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)
  5. Department of Astronomy, University of Virginia, 530 McCormick Road, Charlottesville, VA 22904 (United States)
  6. Núcleo de Astronomía de la Facultad de Ingeniería, Universidad Diego Portales, Av. Ejército Libertador 441, Santiago (Chile)
  7. Department of Physics, University of Crete, GR-71003 Heraklion (Greece)
  8. Spitzer Science Center, California Institute of Technology, MS 220-6, Pasadena, CA 91125 (United States)
  9. Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands)
  10. National Radio Astronomy Observatory, Charlottesville, VA 22904 (United States)
  11. School of Space Science and Physics, Shandong University at Weihai, Weihai, Shandong 264209 (China)
  12. National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States)
Publication Date:
OSTI Identifier:
22524882
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 820; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CARBON MONOXIDE; CORRECTIONS; CORRELATIONS; COSMIC DUST; DECOUPLING; EMISSION SPECTRA; GALAXIES; GALAXY CLUSTERS; GALAXY NUCLEI; HEATING; IMAGES; PROBES; RESOLUTION; STAR CLUSTERS; STAR EVOLUTION; STARS

Citation Formats

Zhao, Yinghe, Lu, Nanyao, Xu, C. Kevin, Appleton, Philip, Murphy, Eric, Gao, Yu, Barcos-Munõz, Loreto, Díaz-Santos, Tanio, Charmandaris, Vassilis, Armus, Lee, Van der Werf, Paul, Evans, Aaron, Cao, Chen, and Inami, Hanae, E-mail: zhaoyinghe@gmail.com. ALMA IMAGING OF THE CO (6-5) LINE EMISSION IN NGC 7130. United States: N. p., 2016. Web. doi:10.3847/0004-637X/820/2/118.
Zhao, Yinghe, Lu, Nanyao, Xu, C. Kevin, Appleton, Philip, Murphy, Eric, Gao, Yu, Barcos-Munõz, Loreto, Díaz-Santos, Tanio, Charmandaris, Vassilis, Armus, Lee, Van der Werf, Paul, Evans, Aaron, Cao, Chen, & Inami, Hanae, E-mail: zhaoyinghe@gmail.com. ALMA IMAGING OF THE CO (6-5) LINE EMISSION IN NGC 7130. United States. doi:10.3847/0004-637X/820/2/118.
Zhao, Yinghe, Lu, Nanyao, Xu, C. Kevin, Appleton, Philip, Murphy, Eric, Gao, Yu, Barcos-Munõz, Loreto, Díaz-Santos, Tanio, Charmandaris, Vassilis, Armus, Lee, Van der Werf, Paul, Evans, Aaron, Cao, Chen, and Inami, Hanae, E-mail: zhaoyinghe@gmail.com. Fri . "ALMA IMAGING OF THE CO (6-5) LINE EMISSION IN NGC 7130". United States. doi:10.3847/0004-637X/820/2/118.
@article{osti_22524882,
title = {ALMA IMAGING OF THE CO (6-5) LINE EMISSION IN NGC 7130},
author = {Zhao, Yinghe and Lu, Nanyao and Xu, C. Kevin and Appleton, Philip and Murphy, Eric and Gao, Yu and Barcos-Munõz, Loreto and Díaz-Santos, Tanio and Charmandaris, Vassilis and Armus, Lee and Van der Werf, Paul and Evans, Aaron and Cao, Chen and Inami, Hanae, E-mail: zhaoyinghe@gmail.com},
abstractNote = {In this paper, we report our high-resolution (0.″20 × 0.″14 or ∼70 × 49 pc) observations of the CO(6-5) line emission, which probes warm and dense molecular gas, and the 434 μm dust continuum in the nuclear region of NGC 7130, obtained with the Atacama Large Millimeter Array (ALMA). The CO line and dust continuum fluxes detected in our ALMA observations are 1230 ± 74 Jy km s{sup −1} and 814 ± 52 mJy, respectively, which account for 100% and 51% of their total fluxes. We find that the CO(6-5) and dust emissions are generally spatially correlated, but their brightest peaks show an offset of ∼70 pc, suggesting that the gas and dust emissions may start decoupling at this physical scale. The brightest peak of the CO(6-5) emission does not spatially correspond to the radio continuum peak, which is likely dominated by an active galactic nucleus (AGN). This, together with our additional quantitative analysis, suggests that the heating contribution of the AGN to the CO(6-5) emission in NGC 7130 is negligible. The CO(6-5) and the extinction-corrected Pa-α maps display striking differences, suggestive of either a breakdown of the correlation between warm dense gas and star formation at linear scales of <100 pc or a large uncertainty in our extinction correction to the observed Pa-α image. Over a larger scale of ∼2.1 kpc, the double-lobed structure found in the CO(6-5) emission agrees well with the dust lanes in the optical/near-infrared images.},
doi = {10.3847/0004-637X/820/2/118},
journal = {Astrophysical Journal},
number = 2,
volume = 820,
place = {United States},
year = {Fri Apr 01 00:00:00 EDT 2016},
month = {Fri Apr 01 00:00:00 EDT 2016}
}
  • We present spatially resolved (∼50 pc) imaging of molecular gas species in the central kiloparsec of the nearby starburst galaxy NGC 253, based on observations taken with the Atacama Large Millimeter/submillimeter Array. A total of 50 molecular lines are detected over a 13 GHz bandwidth imaged in the 3 mm band. Unambiguous identifications are assigned for 27 lines. Based on the measured high CO/C{sup 17}O isotopic line ratio (≳350), we show that {sup 12}CO(1-0) has moderate optical depths. A comparison of the HCN and HCO{sup +} with their {sup 13}C-substituted isotopologues shows that the HCN(1-0) and HCO{sup +}(1-0) lines have optical depths at leastmore » comparable to CO(1-0). H{sup 13}CN/H{sup 13}CO{sup +} (and H{sup 13}CN/HN{sup 13}C) line ratios provide tighter constraints on dense gas properties in this starburst. SiO has elevated abundances across the nucleus. HNCO has the most distinctive morphology of all the bright lines, with its global luminosity dominated by the outer parts of the central region. The dramatic variation seen in the HNCO/SiO line ratio suggests that some of the chemical signatures of shocked gas are being erased in the presence of dominating central radiation fields (traced by C{sub 2}H and CN). High density molecular gas tracers (including HCN, HCO{sup +}, and CN) are detected at the base of the molecular outflow. We also detect hydrogen β recombination lines that, like their α counterparts, show compact, centrally peaked morphologies, distinct from the molecular gas tracers. A number of sulfur based species are mapped (CS, SO, NS, C{sub 2}S, H{sub 2}CS, and CH{sub 3}SH) and have morphologies similar to SiO.« less
  • We present the results of our ALMA Cycle 2 high angular resolution (0.″1–0.″2) observations of the nuclear region of the nearby well-studied type-2 active galactic nucleus (AGN), NGC 1068, at HCN J = 3–2 and HCO{sup +} J = 3–2 emission lines. For the first time, due to a higher angular resolution than previous studies, we clearly detected dense molecular gas emission at the putative AGN location, identified as a ∼1.1 mm (∼266 GHz) continuum emission peak, by separating this emission from brighter emission located at 0.″5–2.″0 on the eastern and western sides of the AGN. The estimated intrinsic molecularmore » emission size and dense molecular mass, which are thought to be associated with the putative dusty molecular torus around an AGN, were ∼10 pc and ∼several × 10{sup 5} M {sub ⊙}, respectively. HCN-to-HCO{sup +} J = 3–2 flux ratios substantially higher than unity were found throughout the nuclear region of NGC 1068. The continuum emission displayed an elongated morphology along the direction of the radio jet located at the northern side of the AGN, as well as a weak spatially-resolved component at ∼2.″0 on the southwestern side of the AGN. The latter component most likely originated from star formation, with the estimated luminosity more than one order of magnitude lower than the luminosity of the central AGN. No vibrationally excited ( v {sub 2} = 1f) J = 3–2 emission lines were detected for HCN and HCO{sup +} across the field of view.« less
  • A Suzaku X-ray observation of NGC 4051 taken during 2005 November reveals line emission at 5.44 keV in the rest frame of the galaxy which does not have an obvious origin in known rest-frame atomic transitions. The improvement to the fit statistic when this line is accounted for establishes its reality at >99.9% confidence: we have also verified that the line is detected in the three X-ray Imaging Spectrometer units independently. Comparison between the data and Monte Carlo simulations shows that the probability of the line being a statistical fluctuation is p < 3.3 x 10{sup -4}. Consideration of threemore » independent line detections in Suzaku data taken at different epochs yields a probability p < 3 x 10{sup -11} and thus conclusively demonstrates that it cannot be a statistical fluctuation in the data. The new line and a strong component of Fe Kalpha emission from neutral material are prominent when the source flux is low, during 2005. Spectra from 2008 show evidence for a line consistent with having the same flux and energy as that observed during 2005, but inconsistent with having a constant equivalent width against the observed continuum. The stability of the line flux and energy suggests that it may not arise in transient hotspots, as has been suggested for similar lines in other sources, but could arise from a special location in the reprocessor, such as the inner edge of the accretion disk. Alternatively, the line energy may be explained by spallation of Fe into Cr, as discussed in a companion paper.« less
  • We report ALMA Band 7 (350 GHz) imaging at 0.''4-0.''6 resolution and Band 9 (696 GHz) at ∼0.''25 resolution of the luminous IR galaxies Arp 220 and NGC 6240. The long wavelength dust continuum is used to estimate interstellar medium masses for Arp 220 east and west and NGC 6240 of 1.9, 4.2, and 1.6 × 10{sup 9} M {sub ☉}within radii of 69, 65, and 190 pc. The HCN emission was modeled to derive the emissivity distribution as a function of radius and the kinematics of each nuclear disk, yielding dynamical masses consistent with the masses and sizes derived from the dustmore » emission. In Arp 220, the major dust and gas concentrations are at radii less than 50 pc in both counter-rotating nuclear disks. The thickness of the disks in Arp 220 estimated from the velocity dispersion and rotation velocities are 10-20 pc and the mean gas densities are n{sub H{sub 2}}∼10{sup 5} cm{sup –3} at R <50 pc. We develop an analytic treatment for the molecular excitation (including photon trapping), yielding volume densities for both the HCN and CS emission with n {sub H2} ∼ 2 × 10{sup 5} cm{sup –3}. The agreement of the mean density from the total mass and size with that required for excitation suggests that the volume is essentially filled with dense gas, i.e., it is not cloudy or like swiss cheese.« less
  • Infrared emission-line images of the v = 1-0 S(1) transition of molecular hydrogen and Br-gamma recombination line of atomic hydrogen which cover the entire extent of NGC 6720, the Ring nebula. The maps presented here are the highest angular resolution images of these transitions yet produced for this object and have very low relative positional uncertainty. As a result, the spatial stratification of the ionized and shocked molecular zones within the nebula is clearly resolved. These data, and data from the Infrared Astronomical Satellite, are used to determine the H/sub 2/, H I, and dust mass within the nebula. Energymore » sources for the dust heating, formation and destruction of the H/sub 2/, and overall evolution of the nebula are also discussed. 38 references.« less